TY - JOUR T1 - A synthetic pseudosubstrate peptide of protein kinase C inhibits the phorbol-12,13-dibutyrate effect on permeabilized coronary artery smooth muscle. JF - Molecular Pharmacology JO - Mol Pharmacol SP - 621 LP - 624 VL - 39 IS - 5 AU - T S Guthrie AU - J Tsuji AU - J N Wells Y1 - 1991/05/01 UR - http://molpharm.aspetjournals.org/content/39/5/621.abstract N2 - We have studied the effects of a synthetic peptide that is based on the autoinhibitory domain of protein kinase C on tension development in detergent-permeabilized coronary artery smooth muscle. This peptide inhibited two forms of protein kinase C that were isolated from the coronary artery media layer by hydroxylapatite chromatography, with apparent Ki values in the 5-8 microM range. Contractions induced by calcium in the permeabilized arteries were not affected by the peptide (30 microM). Potentiation of calcium-induced contractions by 1 microM phorbol-12,13-dibutyrate was partially inhibited by 10 microM peptide and was completely abolished by 30 microM peptide. These results indicate that phorbol-12,13-dibutyrate potentiates calcium-induced contractions of permeabilized coronary arteries by activation of protein kinase C, but activated protein kinase C is not a requirement for the induction of contractions by calcium alone. ER -